1. Field of the Invention
This invention relates to an optical receiver.
2. Background Art
In an optically coupled device or an optical transmission device, the optical receiver which receives an optical signal and converts the optical signal to an electric signal is used.
In the optically coupled device or the optical transmission device, lowering of temperature dependency of transmission delay time and input sensitivity of the signal is required. However, these devices are composed of, a light-emitting element, an optical receiving element, a trans-impedance amplifier, a comparator circuit, an output amplifier, and so forth, and the characteristics such as transmission delay time and input sensitivity often lower with temperature rising.
There is a technology disclosure example for an optical receiver for suppressing influence of change of the surrounding temperature (JP-A 2006-5761 (Kokai)). In this technology disclosure example, a preamplifier, an average detection circuit, a voltage-current conversion circuit, and a preamplifier replica circuit are included, and the value of current split-flowing from an input part of the preamplifier is controlled to be a constant value without receiving the influence of voltage fluctuation and surrounding temperature change.
However, even when this technology disclosure example is used, the temperature dependency of the input sensitivity and the transmission delay time cannot sufficiently be reduced.